1. Field of the Present Disclosure
The present disclosure relates to an image processing apparatus and a non-transitory computer readable recording medium storing an image processing program.
2. Description of the Related Art
An image processing apparatus detects an area such as photograph, figure, table or halftone dots in an image.
Further, a system extracts a circumscribed rectangle of black connection pixels in an image, and classifies a property of the rectangle into a character, a ruled line, a table, a figure, a graph, or the like on the basis of the shape of the circumscribed rectangle and the data of its inside.
For example, for generating a highly compressed PDF (Portable Document Format) file, areas in an image are classified into predetermined plural properties, image data of each area is encoded and compressed in a manner (a resolution, an encoding method, and the like) corresponding to its property.
When encoding and compressing the image data of each area in the image in such manner, a graph is extracted as a halftone dot area or a table area and therefore the graph is encoded and compressed in a manner suitable to a halftone dot area or a table area. Consequently, if a graph includes a small character, the image quality of the small character is dropped by encoding and compressing in such manner and the visibility of the small character is dropped. FIGS. 4A and 4B show examples of a graph including a small character. In some cases, halftone dot areas 101 to 103 in a graph such as a bar graph, a circle graph or the like include characters 111 to 113 as shown in FIG. 4A, and halftone dot areas 101 to 103 in a graph such as a bar graph, a circle graph or the like have characters 111 to 113 in neighborhood thereof as shown in FIG. 4B.